Fixed bend assembly

ABSTRACT

There is provided a fixed bend assembly comprising a first bend housing, a second bend housing and an annular spacer. The first bend housing comprises a tubular housing with a first end, a second end and a bore therethrough, wherein a longitudinal axis of the first end of the first bend housing is offset relative to a longitudinal axis of the second end of the first bend housing. The second bend housing comprises a tubular housing with a first end, a second end and a bore therethrough, wherein a longitudinal axis of the first end of the second bend housing is offset relative to a longitudinal axis of the second end of the second bend housing. The annular spacer comprises an external surface and an internal surface extending between a first end and an opposed second end, wherein a width of the annular spacer between the first end and the second end is consistent around the annular spacer. The first or second end of the first bend housing comprises a first connection end and the first or second end of the second bend housing comprises a second connection end. One of the first or second connection ends is a male connection with an externally threaded surface and the other of the first or second connection ends is a female connection with an internally threaded surface, wherein the first bend housing and second bend housing are connectable by threaded connection of the male and female connection with the annular spacer positioned between the first bend housing and the second bend housing. The width of the annular spacer determines a circumferential orientation of a high side of the first bend housing relative to a high side of the second bend housing when the first bend housing and second bend housing are connected by the threaded connection to provide a total bend angle of the fixed bend assembly, whereby the total bend angle is an angle between a longitudinal axis of one end of the fixed bend assembly and a longitudinal axis of the opposite end of the fixed bend assembly when the first bend housing and the second bend housing are connected.

TECHNICAL FIELD

The present disclosure is directed to a fixed bend assembly and in particular a fixed bend assembly for a downhole drilling tool.

BACKGROUND

In drilling of oil and gas wells, the drill bit is driven by a downhole mud motor located at the end of a drill string. In “directional” drilling the borehole deviates at an angle to the vertical. The angle is created by placing a bend or bent housing or sub in the drill string that causes the borehole to deviate from vertical as drilling progresses. These bend (bent) housings or subs are short tubular sections that are “bent” to create an angular offset between the respective ends of the tubular section causing the drill string to deviate from vertical as drilling progresses. The current options available for directional drilling are an adjustable assembly or a fixed bend.

A typical adjustable assembly is shown in Prior Art FIG. 1. The adjustable assembly comprises a first tubular member 80, a second tubular member 82 and a central tubular member 84 arranged in end to end relation with the central tubular member 84 positioned between the first and second tubular members 80, 82. A first longitudinal axis 81 of the first tubular member 80 is offset relative to a second longitudinal axis 83 of the second tubular member 82 thereby creating a bend. Central tubular member 84 has an internal spline and engages with an external spline or key arrangement of an internal tubular member 86. One end of the internal tubular member 86 is externally threaded and engages with an internally threaded end of the first tubular member 80. The other end of the internal tubular member 86 is externally threaded and engages with an internally threaded end of the second tubular member 82. The first and second tubular members 80, 82 are torqued to and across the internal tubular member 86, locking the first, second and central tubular members 80, 82, 84 together.

The adjustable assembly allows the angle of the bend to be adjusted and yields flexibility in the variety of bend angles that can be set on a single downhole motor. However, these adjustable assemblies generally have a higher risk of connection back offs or cracking downhole under aggressive drilling conditions and/or reaming applications. This makes them less appealing to some customers. Initial costs are higher due to the adjustable assembly requiring 3-4 major components in the design with higher complexities to manufacture. Repair costs can also be high due to more complex geometries in the design and the number of components requiring repair.

A typical fixed bend is shown in Prior Art FIG. 2. The fixed bend comprises a tubular fixed bend housing 90 with a bore therethrough. The fixed bend housing 90 is made up of a straight section 90 a and a bend section 90 b. A longitudinal axis 94 of the bend section 90 b is offset relative to a longitudinal axis 92 of the straight section 90 a creating a bend in the fixed bend housing 90 and thus a bend in the drill string.

Fixed bends are more robust than adjustable assemblies and have a simplistic design consisting of only one major component (fixed bend housing 90). This makes them popular with companies wanting to drill in more aggressive conditions. A fixed bend is less expensive to manufacture than an adjustable assembly, but a single motor requires a full set of fixed bend assets with different bend angles that sit idle in inventory with only one fixed bend being used at a time. Typically, 3-4 fixed bend designs are required for a single motor. Fixed bends are prone to relaxing (bend angle drops) during operation or when the hard surface pad is repaired. Once this bend angle changes it can be re-classified as a lower bend angle, but there is a threshold at which point the updated bend angle is not required and can no longer be used. This typically occurs long before the actual life span of the part is complete.

SUMMARY OF INVENTION

According to a first aspect there is provided a fixed bend assembly comprising a first bend housing, a second bend housing and an annular spacer. The first bend housing comprises a tubular housing with a first end, a second end and a bore therethrough, wherein a longitudinal axis of the first end of the first bend housing is offset relative to a longitudinal axis of the second end of the first bend housing. The second bend housing comprises a tubular housing with a first end, a second end and a bore therethrough, wherein a longitudinal axis of the first end of the second bend housing is offset relative to a longitudinal axis of the second end of the second bend housing. The annular spacer comprises an external surface and an internal surface extending between a first end and an opposed second end, wherein a width of the annular spacer between the first end and the second end is consistent around the annular spacer. The first or second end of the first bend housing comprises a first connection end and the first or second end of the second bend housing comprises a second connection end. One of the first or second connection ends is a male connection with an externally threaded surface and the other of the first or second connection ends is a female connection with an internally threaded surface, wherein the first bend housing and second bend housing are connectable by threaded connection of the male and female connection with the annular spacer positioned between the first bend housing and the second bend housing. The width of the annular spacer determines a circumferential orientation of a high side of the first bend housing relative to a high side of the second bend housing when the first bend housing and second bend housing are connected by the threaded connection to provide a total bend angle of the fixed bend assembly, whereby the total bend angle is an angle between a longitudinal axis of one end of the fixed bend assembly and a longitudinal axis of the opposite end of the fixed bend assembly when the first bend housing and the second bend housing are connected.

The longitudinal axis of the first end of the first bend housing may be offset relative to the longitudinal axis of the second end of the first bend housing by a first angle and the longitudinal axis of the first end of the second bend housing may be offset relative to the longitudinal axis of the second end of the second bend housing by a second angle. The first angle may be greater than the second angle.

The annular spacer may be received on the male connection with one of the first or second ends of the annular spacer being a male connection end which abuts an annular shoulder of an external surface of the male connection and the other of the first or second ends of the annular spacer being a female connection end which abuts a blunt end of the female connection when there is threaded connection of the male and female connection.

The internal surface, the male connection end, or both the internal surface and the male connection end of the annular spacer may have a design feature which engages with a corresponding design feature on the external surface, the annular shoulder, or both the external surface and the annular shoulder of the male connection respectively to fix the annular spacer in position relative to the male connection. The external surface of the annular spacer may have a first mark thereon and the external surface of the female connection may have a second mark thereon and positioning of the first and second marks may be such that a desired total bend angle of the fixed bend assembly is achieved by alignment of the first mark and the second mark when there is threaded connection of the male and female connection.

The female connection end of the annular spacer may have a design feature which engages with a corresponding design feature on the blunt end of the female connection to fix the annular spacer in position relative to the female connection. The external surface of the annular spacer may have a first mark thereon and an external surface of the first or second bend housing that includes the male connection may have a second mark thereon and positioning of the first and second marks may be such that a desired total bend angle of the fixed bend assembly is achieved by alignment of the first mark and the second mark when there is threaded connection of the male and female connection.

The annular spacer may be received within the female connection with one of the first or second ends of the annular spacer abutting a blunt end of the male connection and the other of the first or second ends of the annular spacer abutting an annular shoulder of an internal surface of the female connection when there is threaded connection of the male and female connection.

The fixed bend assembly may comprise a pair of spacers with a first annular spacer comprising an external surface and an internal surface extending between a first male connection end and a first female connection end, and a second annular spacer comprising an external surface and an internal surface extending between a second male connection end and a second female connection end. The male connection may have a first male connection surface and the female connection may have a first female connection surface. The first male connection surface may abut the first male connection end of the first annular spacer and the first female connection surface may abut the first female connection end of the first annular spacer when there is threaded connection of the male and female connection. The male connection may have a second male connection surface and the female connection may have a second female connection surface. The second male connection surface may abut the second male connection end of the second annular spacer and the second female connection surface may abut the second female connection end of the second annular spacer when there is threaded connection of the male and female connection.

The first male connection surface may be an annular shoulder of an external surface of the male connection and the first female connection surface may be a blunt end of the female connection. The second male connection surface may be a blunt end of the male connection and the second female connection surface may be an annular shoulder of an internal surface of the female connection. The first annular spacer may be received on the male connection and the second annular spacer may be received within the female connection.

The internal surface, the first male connection end or both the internal surface and the first male connection end of the first annular spacer may have a design feature which engages with a corresponding design feature on the external surface of the male connection, the annular shoulder of the male connection, or both the external surface and the annular shoulder of the male connection respectively to fix the first annular spacer in position relative to the male connection. The external surface of the first annular spacer may have a first mark thereon and an external surface of the female connection may have a second mark thereon and positioning of the first and second marks may be such that a desired total bend angle of the fixed bend assembly is achieved by alignment of the first mark and the second mark when there is threaded connection of the male and female connection.

The first female connection end of the first annular spacer may have a design feature which engages with a design feature on the blunt end of the female connection to fix the first annular spacer in position relative to the female connection. The external surface of the first annular spacer may have a first mark thereon and an external surface of the first or second bend housing that includes the male connection may have a second mark thereon and positioning of the first and second marks may be such that a desired total bend angle of the fixed bend assembly is achieved by alignment of the first mark and the second mark when there is threaded connection of the male and female connection.

According to another aspect, there is provided a kit comprising a first bend housing, a second bend housing, and a plurality of annular spacers. The first bend housing comprises a tubular housing with a first end, a second end and a bore therethrough, wherein a longitudinal axis of the first end of the first bend housing is offset relative to a longitudinal axis of the second end of the first bend housing. The second bend housing comprises a tubular housing with a first end, a second end and a bore therethrough, wherein a longitudinal axis of the first end of the second bend housing is offset relative to a longitudinal axis of the second end of the second bend housing. Each of the plurality of annular spacers comprises an external surface and an internal surface extending between a first end and a second end, wherein a width of the annular spacer between the first end and the second end is different for different annular spacers of the plurality of annular spacers. The first or second end of the first bend housing is configured to connect with the first or second end of the second bend housing through a releasable connection to form a fixed bend assembly with one of the plurality of annular spacers positioned between the first bend housing and the second bend housing when the first bend housing and the second bend housing are connected by the releasable connection. A total bend angle of the fixed bend assembly is variable by positioning different annular spacers of the plurality of annular spacers between the first bend housing and the second bend housing, whereby the total bend angle of the fixed bend assembly is an angle between a longitudinal axis of one end of the fixed bend assembly and a longitudinal axis of the opposite end of the fixed bend assembly when the first bend housing and the second bend housing are connected by the releasable connection.

The longitudinal axis of the first end of the first bend housing may be offset relative to the longitudinal axis of the second end of the first bend housing by a first angle and the longitudinal axis of the first end of the second bend housing may be offset relative to the longitudinal axis of the second end of the second bend housing by a second angle. The first angle may be greater than the second angle.

The first or second end of the first bend housing configured to connect with the first or second end of the second bend housing may comprise a first connection end, and the first or second end of the second bend housing configured to connect with the first or second end of the first bend housing may comprise a second connection end. One of the first or second connection ends may be a male connection and the other of the first or second connection ends may be a female connection, and the releasable connection may comprise a male and female connection.

The male connection may have an externally threaded surface and the female connection may have an internally threaded surface, and the releasable connection may be a threaded connection of the male and female connection.

The annular spacer may be received on the male connection and one of the first or second ends of the annular spacer may be a male connection end which abuts an annular shoulder of an external surface of the male connection and the other of the first or second ends of the annular spacer may be a female connection end which abuts a blunt end of the female connection when there is connection of the male and female connection.

The internal surface, the male connection end, or both the internal surface and the male connection end of at least one annular spacer of the plurality of annular spacers may have a design feature which engages with a corresponding design feature on the external surface of the male connection, the annular shoulder, or both the external surface and the annular shoulder of the male connection respectively to fix the at least one annular spacer in position relative to the male connection. The external surface of the at least one annular spacer may have a first mark thereon and the external surface of the female connection may have a second mark thereon and positioning of the first and second marks may be such that a desired total bend angle of the fixed bend assembly is achieved by alignment of the first mark and the second mark when there is connection of the male and female connection.

The female connection end of at least one annular spacer of the plurality of annular spacers may have a design feature which engages with a corresponding design feature on the blunt end of the female connection to fix the at least one annular spacer in position relative to the female connection. The external surface of the at least one annular spacer may have a first mark thereon and an external surface of the first or second bend housing that includes the male connection may have a second mark thereon and positioning of the first and second marks may be such that a desired total bend angle of the fixed bend assembly is achieved by alignment of the first mark and the second mark when there is connection of the male and female connection.

The annular spacer may be received within the female connection with one of the first or second ends of the annular spacer abutting a blunt end of the male connection and the other of the first or second ends of the annular spacer abutting an annular shoulder of an internal surface of the female connection when there is connection of the male and female connection.

According to another aspect, there is provided a kit comprising a first bend housing, a second bend housing, and a plurality of pairs of annular spacers. The first bend housing comprises a tubular housing with a first end, a second end and a bore therethrough, wherein a longitudinal axis of the first end of the first bend housing is offset relative to a longitudinal axis of the second end of the first bend housing. The second bend housing comprises a tubular housing with a first end, a second end and a bore therethrough, wherein a longitudinal axis of the first end of the second bend housing is offset relative to a longitudinal axis of the second end of the second bend housing. Each pair of annular spacers comprises a first annular spacer and a second annular spacer, the first annular spacer comprising an external surface and an internal surface extending between a first male connection end and a first female connection end, the second annular spacer comprising an external surface and an internal surface extending between a second male connection end and a second female connection end, wherein a width of the first annular spacer between the first male connection end and the first female connection end and/or a width of the second annular spacer between the second male connection end and the second female connection end is different for different pairs of annular spacers of the plurality of pairs of annular spacers. The first or second end of the first bend housing comprises a first connection end and the first or second end of the second bend housing comprises a second connection end, and wherein one of the first or second connection ends is a male connection with a first male connection surface and a second male connection surface and the other of the first or second connection ends is a female connection with a first female connection surface and a second female connection surface, wherein the male connection and the female connection are configured to releasable connect to form a fixed bend assembly with the first annular spacer positioned between the first male connection surface and the first female connection surface and the second annular spacer positioned between the second male connection surface and the second female connection surface when there is connection of the male and female connection. A total bend angle of the fixed bend assembly is variable by positioning different pairs of the different pairs of annular spacers between the male and female connection surfaces and connecting the male and female connection, whereby the total bend angle of the fixed bend assembly is an angle between a longitudinal axis of one end of the fixed bend assembly and a longitudinal axis of the opposite end of the fixed bend assembly when the first bend housing and the second bend housing are connected.

The longitudinal axis of the first end of the first bend housing may be offset relative to the longitudinal axis of the second end of the first bend housing by a first angle and the longitudinal axis of the first end of the second bend housing may be offset relative to the longitudinal axis of the second end of the second bend housing by a second angle. The first angle may be greater than the second angle.

The male connection may have an externally threaded surface and the female connection may have an internally threaded surface, and the releasable connection may be a threaded connection of the male and female connection.

The first male connection surface may be an annular shoulder of an external surface of the male connection and the first female connection surface may be a blunt end of the female connection, the second male connection surface may be a blunt end of the male connection and the second female connection surface may be an annular shoulder of an internal surface of the female connection, wherein the first annular spacer may be received on the male connection with the first male connection end abutting the annular shoulder of the male connection and the first female connection end abutting the blunt end of the female connection when there is connection of the male and female connection. The second annular spacer may be received within the female connection with the second male connection end abutting the blunt end of the male connection surface and the second female connection end abutting the annular shoulder of the female connection when there is connection of the male and female connection.

The internal surface, the first male connection end or both the internal surface and the first male connection end of the first annular spacer may have a design feature which engages with a corresponding design feature on the external surface, the annular shoulder, or both the external surface and the annular shoulder of the male connection respectively to fix the first annular spacer in position relative to the male connection. The external surface of the first annular spacer may have a first mark thereon and an external surface of the female connection may have a second mark thereon and positioning of the first and second marks may be such that a desired total bend angle of the fixed bend assembly is achieved by alignment of the first mark and the second mark when there is connection of the male and female connection.

The first female connection end of the first annular spacer may have a design feature which engages with a design feature on the blunt end of the female connection to fix the first annular spacer in position relative to the female connection.

The external surface of the first annular spacer may have a first mark thereon and an external surface of the first or second bend housing that includes the male connection may have a second mark thereon and positioning of the first and second marks may be such that a desired total bend angle of the fixed bend assembly is achieved by alignment of the first mark and the second mark when there is connection of the male and female connection.

According to another aspect there is provided a multiple angle fixed bend assembly comprising a fixed bend housing and an offset bend housing. The fixed bend housing comprises a tubular housing with a first end, a second end and a bore therethrough. A longitudinal axis of the first end of the fixed bend housing is offset relative to a longitudinal axis of the second end of the fixed bend housing. The offset bend housing comprises a tubular housing with a first end, a second end and a bore therethrough. A longitudinal axis of the first end of the offset bend housing is offset relative to a longitudinal axis of the second end of the offset bend housing. The first or second end of the fixed bend housing is configured to connect with the first or second end of the offset bend housing through a releasable connection that allows variation in the axial orientation of a high side of the offset bend housing relative to a high side of the fixed bend housing thereby providing variation of a total bend angle of the assembly, whereby the total bend angle of the assembly is an angle between a longitudinal axis of one end of the multiple angle fixed bend assembly and a longitudinal axis of the opposite end of the multiple angle fixed bend assembly when the fixed bend housing and the offset bend housing are connected by the releasable connection.

The fixed bend housing may have a bend along its length such that the longitudinal axis of the first end of the fixed bend housing is offset relative to the longitudinal axis of the second end of the fixed bend housing. The offset bend housing may have a bend along its length such that the longitudinal axis of the first end of the offset bend housing is offset relative to the longitudinal axis of the second end of the offset bend housing.

The first or second end of the fixed bend housing configured to connect with the first or second end of the offset bend housing may comprise a first connection end, and the first or second end of the offset bend housing configured to connect with the first or second end of the fixed bend housing may comprise a second connection end. One of the first or second connection ends may be a male connection and the other of the first or second connection ends may be a female connection such that the releasable connection comprises a male/female connection.

The fixed bend housing may have a bend along its length such that the longitudinal axis of the first end of the fixed bend housing is offset relative to the longitudinal axis of the second end of the fixed bend housing. The offset bend housing may have a bend along its length such that the longitudinal axis of the first end of the offset bend housing is offset relative to the longitudinal axis of the second end of the offset bend housing.

A wall thickness of a high side of the female connection may gradually reduce such that a longitudinal axis of the female connection is offset relative to a longitudinal axis of a remainder of the fixed bend housing or the offset bend housing that includes the female connection.

The male connection may have an externally threaded surface and the female connection may have an internally threaded surface, and the releasable connection may be a threaded connection of the male and female connection. The male connection may have a male connection surface and the female connection may have a female connection surface and the multiple angle fixed bend assembly may be configured to receive an annular spacer comprising an external surface and an internal surface extending between a male connection end and a female connection end. The male connection surface may abut the male connection end and the female connection surface may abut the female connection end when there is threaded connection of the male and female connection.

The male connection surface may be an annular shoulder of an external surface of the male connection and the female connection surface may be a blunt end of the female connection. The annular spacer may be received on the male connection.

An external surface of the fixed bend housing may have a first mark thereon positioned at the high side of the fixed bend housing and an external surface of the offset bend housing may have a second mark thereon positioned at the high side of the offset bend housing.

The male connection surface may be a blunt end of the male connection and the female connection surface may be an annular shoulder of an internal surface of the female connection. The annular spacer may be received within the female connection.

The male connection may have a first male connection surface and the female connection may have a first female connection surface and the multiple angle fixed bend assembly may be configured to receive a first annular spacer comprising an external surface and an internal surface extending between a first male connection end and a first female connection end. The first male connection surface may abut the first male connection end and the first female connection surface may abut the first female connection end when there is threaded connection of the male and female connection. The male connection may have a second male connection surface and the female connection may have a second female connection surface and the multiple angle fixed bend assembly may be configured to receive a second annular spacer comprising an external surface and an internal surface extending between a second male connection end and a second female connection end. The second male connection surface may abut the second male connection end and the second female connection surface may abut the second female connection end when there is threaded connection of the male and female connection.

The first male connection surface may be an annular shoulder of an external surface of the male connection and the first female connection surface may be a blunt end of the female connection. The second male connection surface may be a blunt end of the male connection and the second female connection surface may be an annular shoulder of an internal surface of the female connection. The first annular spacer may be received on the male connection and the second annular spacer may be received within the female connection.

According to another aspect, there is provided a kit comprising: (i) the multiple angle fixed bend assembly of the first aspect, the male connection having a male connection surface and the female connection having a female connection surface; and (ii) a plurality of annular spacers comprising an external surface and an internal surface extending between a male connection end and a female connection end, a length between the male connection end and the female connection end being different for different annular spacers of the plurality of annular spacers. In use one of the plurality of annular spacers is positioned between the male connection surface and the female connection surface and the male connection end abuts the male connection surface and the female connection end abuts the female connection surface when there is threaded connection of the male and female connection. The total bend angle of the assembly may be varied by positioning different ones of the different annular spacers between the male connection surface and the female connection surface and threadedly connecting the male and female connection.

The male connection surface may be an annular shoulder of an external surface of the male connection and the female connection surface may be a blunt end of the female connection. The annular spacer may be received on the male connection.

An external surface of the fixed bend housing may have a first mark thereon positioned at the high side of the fixed bend housing and an external surface of the offset bend housing may have a second mark thereon positioned at the high side of the offset bend housing.

The internal surface, the male connection end, or both the internal surface and the male connection end of at least one annular spacer of the plurality of annular spacers may have a design feature which engages with a corresponding design feature on the male connection surface, the external surface of the male connection, or the male connection surface and the external surface of the male connection respectively to fix the at least one annular spacer in position relative to the male connection. The external surface of the at least one annular spacer may have a first mark thereon and the external surface of the female connection may have a second mark thereon and positioning of the first and second marks is such that a desired total bend angle of the assembly is achieved by alignment of the first mark and the second mark when there is threaded connection of the male and female connection.

The female connection end of at least one annular spacer of the plurality of annular spacers may have a design feature which engages with a corresponding design feature on the female connection surface to fix the at least one annular spacer in position relative to the female connection. The external surface of the at least one annular spacer may have a first mark thereon and an external surface of the offset bend housing or the fixed bend housing that includes the male connection may have a second mark thereon and positioning of the first and second marks is such that a desired total bend angle of the assembly is achieved by alignment of the first mark and the second mark when there is threaded connection of the male and female connection.

The male connection surface may be a blunt end of the male connection and the female connection surface may be an annular shoulder of an internal surface of the female connection. The annular spacer may be received within the female connection.

According to another aspect, there is provided a kit comprising: (i) the multiple angle fixed bend assembly of the first aspect, the male connection having a first male connection surface and a second male connection surface, and the female connection having a first female connection surface and a second female connection surface; and (ii) a plurality of pairs of annular spacers, each pair of annular spacers comprising a first annular spacer and a second annular spacer, the first annular spacer comprising an external surface and an internal surface extending between a first male connection end and a first female connection end, the second annular spacer comprising an external surface and an internal surface extending between a second male connection end and a second female connection end, a length between the first male connection end and the first female connection end and a length between the second male connection end and the second female connection end being different for different pairs of annular spacers of the plurality of annular spacers. In use the first annular spacer of one of the pairs of annular spacers is positioned between the first male connection surface and the first female connection surface and the second annular spacer is positioned between the second male connection surface and the second female connection surface. The first male connection end abuts the first male connection surface, the first female connection end abuts the first female connection surface, the second male connection end abuts the second male connection surface, and the second female connection end abuts the second female connection surface when there is threaded connection of the male and female connection. The total bend angle of the assembly is varied by positioning different pairs of the different pairs of annular spacers between the male connection surfaces and the female connection surfaces and threadedly connecting the male and female connection.

The first male connection surface may be an annular shoulder of an external surface of the male connection and the first female connection surface may be a blunt end of the female connection. The second male connection surface may be a blunt end of the male connection and the second female connection surface may be an annular shoulder of an internal surface of the female connection. The first annular spacer may be received on the male connection and the second annular spacer may be received within the female connection.

An external surface of the fixed bend housing may have a first mark thereon positioned at the high side of the fixed bend housing and an external surface of the offset bend housing may have a second mark thereon positioned at the high side of the offset bend housing.

The internal surface, the first male connection end or both the internal surface and the first male connection end of the first annular spacer may have a design feature which engages with a corresponding design feature on the first male connection surface, the external surface of the male connection, or the first male connection surface and the external surface of the male connection respectively to fix the first annular spacer in position relative to the male connection. The external surface of the first annular spacer may have a first mark thereon and an external surface of the female connection may have a second mark thereon and positioning of the first and second marks is such that a desired total bend angle of the assembly is achieved by alignment of the first mark and the second mark when there is threaded connection of the male and female connection.

The first female connection end of the first annular spacer may have a design feature which engages with a design feature on the first female connection surface to fix the first annular spacer in position relative to the female connection. The external surface of the first annular spacer may have a first mark thereon and an external surface of the offset bend housing or the fixed bend housing that includes the male connection may have a second mark thereon and positioning of the first and second marks is such that a desired total bend angle of the assembly is achieved by alignment of the first mark and the second mark when there is threaded connection of the male and female connection.

This summary does not necessarily describe the entire scope of all aspects. Other aspects, features and advantages will be apparent to those of ordinary skill in the art upon review of the following description of specific embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

PRIOR ART FIG. 1 is longitudinally sectioned view of a typical adjustable assembly.

PRIOR ART FIG. 2 is longitudinally sectioned view of a typical fixed bend.

FIG. 3A is an end view of a fixed bend assembly according to a first embodiment comprising a first bend housing connected with a second bend housing. The assembly of FIG. 3A is in a first connection position with a first spacer positioned between connection surfaces of the first bend housing and the second bend housing, and the high side of the second bend housing in alignment with the high side of the first bend housing.

FIG. 3B is a longitudinally sectioned view through A-A of FIG. 3A.

FIG. 4A is an end view of the fixed bend assembly of the first embodiment in a second connection position with a second spacer positioned between the connection surfaces of the first bend housing and the second bend housing, and the high side of the second bend housing positioned at 180° relative to the high side of the first bend housing.

FIG. 4B is a longitudinally sectioned view through B-B of FIG. 4A.

FIG. 5A is an end view of a fixed bend assembly according to a second embodiment comprising a first bend housing connected with a second bend housing. The assembly of FIG. 5A is in a first connection position with a pair of spacers positioned between connection surfaces of the first bend housing and the second bend housing, and the high side of the second bend housing in alignment with the high side of the first bend housing.

FIG. 5B is a longitudinally sectioned view through C-C of FIG. 5A.

FIG. 6 is a perspective view of the fixed bend assembly of the first or second embodiment with the high side of the second bend housing positioned at 45° relative to the high side of the first bend housing.

FIG. 7 is a chart showing the total bend angle (TBA) of the fixed bend assembly as a function of the relative angular position (RAP) between the high side of the second bend housing and the high side of the first bend housing.

FIG. 8A is a vector diagram representation of the fixed bend assembly with a relative angular position (RAP) of 117° that produces a total bend angle (TBA) for the assembly of 1.83°.

FIG. 8B is a vector diagram representation of the fixed bend assembly with a RAP of 126° that produces a TBA for the assembly of 1.75°.

FIG. 8C is a vector diagram representation of the fixed bend assembly with a RAP of 117° that produces a TBA for the assembly of 1.83°.

FIG. 8D is a vector diagram representation of the fixed bend assembly with a RAP of 97° that produces a TBA for the assembly of 2.0°.

FIG. 8E is a vector diagram representation of the fixed bend assembly with a RAP of 66° that produces a TBA for the assembly of 2.25°.

FIG. 8F is a vector diagram representation of the fixed bend assembly with a RAP of 0° that produces a TBA for the assembly of 2.5°.

FIG. 8G is a vector diagram representation of the fixed bend assembly with a RAP of 180° that produces a TBA for the assembly of 1.5°.

FIG. 9A is an end view of a fixed bend assembly according to a third embodiment comprising a first bend housing connected with a second bend housing. The assembly of FIG. 9A is in a first connection position with a first spacer positioned between connection surfaces of the first bend housing and the second bend housing, and the high side of the second bend housing in alignment with the high side of the first bend housing.

FIG. 9B is a longitudinally sectioned view through A-A of FIG. 9A.

FIG. 10A is an end view of the fixed bend assembly of the third embodiment in a second connection position with a second spacer positioned between the connection surfaces of the first bend housing and the second bend housing, and the high side of the second bend housing positioned at 180° relative to the high side of the first bend housing.

FIG. 10B is a longitudinally sectioned view through B-B of FIG. 10A.

FIG. 11A is an end view of a fixed bend assembly according to a fourth embodiment comprising a first bend housing connected with a second bend housing. The assembly of FIG. 11A is in a first connection position with a pair of spacers positioned between connection surfaces of the first bend housing and the second bend housing, and the high side of the second bend housing in alignment with the high side of the first bend housing.

FIG. 11B is a longitudinally sectioned view through C-C of FIG. 11A.

FIG. 12 is a perspective view of the fixed bend assembly of the third or fourth embodiment with the high side of the second bend housing positioned at 45° relative to the high side of the first bend housing.

FIG. 13 is a perspective view of the fixed bend assembly of the first or second embodiment with the high side of the second bend housing positioned at 45° relative to the high side of the first bend housing.

FIG. 14 is a perspective view of the fixed bend assembly of the third or fourth embodiment with the high side of the second bend housing positioned at 45° relative to the high side of the first bend housing.

FIG. 15 shows the law of cosines that can be used to calculate the total bend angle (TBA) of the fixed bend assembly once the relative angular position (RAP) is known.

DETAILED DESCRIPTION

Directional terms such as “ top” , “ bottom” , “upper” , “ lower” , “ left” , “right”, “ vertical”, “downhole” and “uphole” are used in the following description for the purpose of providing relative reference only, and are not intended to suggest any limitations on how any article is to be positioned during use, or to be mounted in an assembly or relative to an environment.

The embodiments described herein relate to a fixed bend assembly. The fixed bend assembly may be used with any type of downhole tool requiring a bend for example, but not limited to, a drilling motor.

Referring to FIGS. 3 and 4, there is shown a first embodiment of a fixed bend assembly 1 comprising a first bend housing 10 and a second bend housing 20. The first bend housing 10 comprises a tubular housing with a bore therethrough having a female (box) connection 11 at one end and an externally threaded male (pin) connection 12 at the other end. In alternative embodiments there may be a female connection at both ends or a male connection at both ends of the first bend housing or the female connection and the male connection may be at opposite ends to those shown in FIGS. 3 and 4. In further alternative embodiments the ends of the first bend housing may have different connections to the female and male connection shown in FIGS. 3 and 4.

The first bend housing 10 is made up of a straight section 10 a and a bend section 10 b. The straight section 10 a includes the female connection 11 which can receive a male connection of another tubular section of the drill string, or a drilling motor or other drilling tool. The bend section 10 b includes the male connection 12 and is offset relative to the straight section 10 a creating a bend in the first bend housing 10. The first bend housing 10 has a high side 14 where the bend kicks up. The base bend angle (BBA) is the angle between the longitudinal axis 40 of the straight section 10 a and the longitudinal axis 41 of the bend section 10 b. In other words, the BBA is the angle between the longitudinal axis of one end of the first bend housing 10 and the longitudinal axis of the other end of the first bend housing 10. In the first embodiment shown in FIGS. 3 and 4 the BBA is 2°, however in alternative embodiments, the BBA may be any angle greater than zero degrees. A contact pad 50 is positioned on the low side of the first bend housing 10. In alternative embodiments the contact pad may be positioned anywhere on the first bend housing or on the second bend housing or there may be no contact pad present on either housing. In alternative embodiments, the BBA may be created by another design feature of the first bend housing rather than as a result of a bend in the first bend housing. In these alternative embodiments, the longitudinal axis at one end of the first bend housing is offset relative to the longitudinal axis at the other end of the first bend housing.

The second bend housing 20 comprises a tubular housing with a bore therethrough having an internally threaded female (box) connection 21 at one end and a male (pin) connection 22 at the other end. The male connection 22 can be received in a female connection of another tubular section of the drill string, or a drilling motor or other drilling tool. In alternative embodiments there may be a female connection at both ends or a male connection at both ends of the second bend housing or the female connection and the male connection may be at opposite ends to those shown in FIGS. 3 and 4. In these alternative embodiments one end of the second bend housing releasably connects with one end of the first bend housing through a male/female connection whereby at least one of the connection ends of either the second bend housing or the first bend housing is a male connection and the other connection end is a female connection. In further alternative embodiments the ends of the second bend housing may have different connections to the female and male connection shown in FIGS. 3 and 4. In these alternative embodiments, one end of the first bend housing connects with one end of the second bend housing through a releasable connection.

At a high side 24 of the second bend housing 20, the wall of the female connection 21 gets gradually thicker along the length of the female connection 21 and the wall of the female connection gets gradually thinner along its length on the opposite low side of the second bend housing creating an offset bend angle (OBA) on the connection axis with respect to the longitudinal axis of the remainder of the second bend housing 20. In other words, the OBA is the angle between the longitudinal axis of one end of the second bend housing 20 and the longitudinal axis of the other end of the second bend housing 20. In the first embodiment shown in FIGS. 3 and 4, the OBA of the housing is 0.5°, therefore the longitudinal axis 42 of the male connection 22 of the second bend housing 20 is offset by 0.5° relative to the longitudinal axis 41 of the female connection 21. In alternative embodiments the OBA of the housing may be any amount greater than zero degrees. In further alternative embodiments, the OBA may be created by another design feature of the second bend housing rather than as a result of the configuration of the female connection. In these alternative embodiments, the longitudinal axis at one end of the second bend housing is offset relative to the longitudinal axis at the other end of the second bend housing.

Referring now to FIG. 5, there is shown a second embodiment of a fixed bend assembly 100 comprising the first bend housing 10 shown in FIGS. 3 and 4 and a second bend housing 120. The second bend housing 120 is similar to the second bend housing 20 of the first embodiment shown in FIGS. 3 and 4 and includes an internally threaded female connection 121 at one end and a male connection 122 at the other end. In alternative embodiments there may be a female connection at both ends or a male connection at both ends of the second bend housing or the female connection and the male connection may be at opposite ends to those shown in FIG. 5. In these alternative embodiments one end of the second bend housing releasably connects with one end of the first bend housing through a male/female connection whereby at least one of the connection ends of either the second bend housing or the first bend housing is a male connection and the other connection end is a female connection. In further alternative embodiments the ends of the second bend housing may have different connections to the female and male connection shown in FIG. 5. In these alternative embodiments, one end of the first bend housing connects with one end of the second bend housing through a releasable connection.

As with the second bend housing 20 of the first embodiment, at a high side 124 of the second bend housing 120, the wall of the female connection 121 gets gradually thicker along the length of the female connection 121 creating an offset bend angle (OBA) on the connection axis with respect to the longitudinal axis of the remainder of the second bend housing 120. In the second embodiment shown in FIG. 5, the OBA of the housing is 0.5°, therefore the longitudinal axis 142 of the male connection 122 of the second bend housing 120 is offset by 0.5° relative to the longitudinal axis 41 of the female connection 121. In alternative embodiments the OBA may be any amount greater than zero degrees. In further alternative embodiments, the OBA may be created by another design feature of the second bend housing rather than as a result of the configuration of the female connection. In these alternative embodiments, the longitudinal axis at one end of the second bend housing is offset relative to the longitudinal axis at the other end of the second bend housing.

Referring now to FIGS. 9 and 10, there is shown a third embodiment of a fixed bend assembly 200 comprising the first bend housing 10 of the first embodiment shown in FIGS. 3 and 4 and a second bend housing 220. The second bend housing 220 includes an internally threaded female connection 221 at one end and a male connection 222 at the other end. In alternative embodiments there' may be a female connection at both ends or a male connection at both ends of the second bend housing or the female connection and the male connection may be at opposite ends to those shown in FIGS. 9 and 10. In these alternative embodiments one end of the second bend housing releasably connects with one end of the first bend housing through a male/female connection whereby at least one of the connection ends of either the second bend housing or the first bend housing is a male connection and the other connection end is a female connection. In further alternative embodiments the ends of the second bend housing may have different connections to the female and male connection shown in FIGS. 9 and 10. In these alternative embodiments, one end of the first bend housing connects with one end of the second bend housing through a releasable connection.

The second bend housing 220 is made up of a straight section 220 a and a bend section 220 b, with the bend section 220 b offset relative to the straight section 220 a creating a bend in the second bend housing 220. The offset bend angle (OBA) is the angle between the longitudinal axis 41 of the straight section 220 a and the longitudinal axis 242 of the bend section 220 b. In other words, the OBA is the angle between the longitudinal axis of one end of the second bend housing 220 and the longitudinal axis of the other end of the second bend housing 220. In the third embodiment shown in FIGS. 9 and 10 the OBA is 0.5°, however in alternative embodiments, the OBA may be any angle greater than zero degrees. The second bend housing 220 has a high side 224 where the bend kicks up. In alternative embodiments, the OBA may be created by another design feature of the second bend housing rather than as a result of a bend in the second bend housing. In these alternative embodiments, the longitudinal axis at one end of the second bend housing is offset relative to the longitudinal axis at the other end of the second bend housing.

Referring now to FIG. 11, there is shown a fourth embodiment of a fixed bend assembly 300 comprising the first bend housing 10 shown in FIGS. 3 and 4 and a second bend housing 320. The second bend housing 320 is similar to the second bend housing 220 of the third embodiment shown in FIGS. 9 and 10, and includes an internally threaded female connection 321 at one end and a male connection 322 at the other end. In alternative embodiments there may be a female connection at both ends or a male connection at both ends of the second bend housing or the female connection and the male connection may be at opposite ends to those shown in FIG. 11. In these alternative embodiments one end of the second bend housing releasably connects with one end of the first bend housing through a male/female connection whereby at least one of the connection ends of either the second bend housing or the first bend housing is a male connection and the other connection end is a female connection. In further alternative embodiments the ends of the second bend housing may have different connections to the female and male connection shown in FIG. 11. In these alternative embodiments, one end of the first bend housing connects with one end of the second bend housing through a releasable connection.

As with the second bend housing 220 of the third embodiment, the second bend housing 320 of the fourth embodiment is made up of a straight section 320 a and a bend section 320 b, with the bend section 320 b offset relative to the straight section 320 a creating a bend in the second bend housing 320. The offset bend angle (OBA) is the angle between the longitudinal axis 41 of the straight section 320 a and the longitudinal axis 342 of the bend section 320 b. In other words, the OBA is the angle between the longitudinal axis of one end of the second bend housing 320 and the longitudinal axis of the other end of the second bend housing 320. In the fourth embodiment shown in FIG. 11 the OBA is 0.5°, however in alternative embodiments, the OBA may be any angle greater than zero degrees. The second bend housing 320 has a high side 324 where the bend kicks up. In alternative embodiments, the OBA may be created by another design feature of the second bend housing rather than as a result of a bend in the second bend housing. In these alternative embodiments, the longitudinal axis at one end of the second bend housing is offset relative to the longitudinal axis at the other end of the second bend housing.

During assembly of the first and third embodiments of the fixed bend assembly 1, 200 in the first connection position shown in FIGS. 3 and 9, a first annular spacer 30 is received on the male connection 12 of the first bend housing 10. The first spacer 30 has a first end 30 a and an opposed second end 30 b. The first end 30 a abuts an annular shoulder (male connection surface) 13 on an external surface of the male connection 12. The internally threaded female connection 21, 221 of the second bend housing 20, 220 is threaded onto the externally threaded male connection 12 of the first bend housing 10 until a blunt end (female connection surface) 23, 223 of the female connection 21, 221 abuts the second end 30 b of the first spacer 30. The threaded connection between the male connection 12 and the female connection 21, 221 is then torqued to provide a strong fixed connection between the first bend housing 10 and the second bend housing 20, 220. The width of the first annular spacer 30 between the first end 30 a and the second end 30 b is configured such that when the threaded connection is torqued the second bend housing high side 24, 224 is aligned with the first bend housing high side 14. The total bend angle (TBA) is the angle between the longitudinal axis 40 of female connection 11 of the first bend housing 10 and the longitudinal axis 42, 242 of the male connection 22, 222 of the second bend housing 20, 220. In other words the total bend angle (TBA) is the angle between the longitudinal axis of one end of the fixed bend assembly and the longitudinal axis of the other end of the fixed bend assembly when the first bend housing and the second bend housing are connected together. In the first connection position shown in FIGS. 3 and 9 the TBA is 2.5°.

Assembly of the first and third embodiments of the fixed bend assembly 1, 200 in the second connection position shown in FIGS. 4 and 10 is similar to assembly in the first position shown in FIGS. 3 and 9, however a second annular spacer 31 is used instead of the first annular spacer 30. The second annular spacer 31 has a first end 31 a that abuts the annular shoulder 13 of the male connection 12 and an opposed second end 31 b that abuts the blunt end 23, 223 of the female connection 21, 221 when the first bend housing 10 and second bend housing 20, 220 are connected together. The width of the second spacer 31 between the first end 31 a and the second end 31 b is different to the width of the first spacer 30 between the first end 30 a and the second end 30 b. The width of the second spacer 31 is such that when the threaded connection between the male connection 12 and the female connection 21, 221 is torqued, the second bend housing high side 24, 224 is positioned 180° from the first bend housing high side 14. In this second connection position, the total bend angle (TBA) between the longitudinal axis 40 of female connection 11 of the first bend housing 10 and the longitudinal axis 42, 242 of the male connection 22, 222 of the second bend housing 20, 220 is 1.5°.

The first connection position of the first and third embodiments of the assembly 1, 200 shown in FIGS. 3 and 9 has the maximum TBA of 2.5° and the second connection position of the first and third embodiments of the assembly 1, 200 shown in FIGS. 4 and 10 has the minimum TBA of 1.5° that can be obtained for the first and third embodiments of the assembly 1, 200. It is possible to obtain multiple different TBA between this minimum and maximum TBA using spacers of varying widths to yield the desired TBA for a predetermined torque. The predetermined torque can be set through experimentation to determine the optimal torque for a strong fixed connection between the first bend housing and the second bend housing taking into account deformation of the spacer and compression/stretch of the male connection and female connection. The amount of torque can also be varied by small amounts for fine adjustments to yield a desired total bend angle (TBA). It will be appreciated by somebody skilled in the art, that provision of a first bend housing with a different base bend angle (BBA) to the 2° BBA of the first bend housing 10 in the first and third embodiments of the assembly 1, 200 and/or provision of a second bend housing with a different offset bend angle (OBA) to the 0.5° OBA of the second bend housing 20, 220 in the first and third embodiments of the assembly 1, 200 will result in a different maximum and minimum TBA for the fixed bend assembly.

During assembly of the second and fourth embodiments of the fixed bend assembly 100, 300 in the first connection position shown in FIGS. 5 and 11, a first annular spacer 130 is received on the male connection 12 of the first bend housing 10 and a second annular spacer 131 is received within the female connection 121, 321 of the second bend housing 120, 320. The internally threaded female connection 121, 321 of the second bend housing 120, 320 is then threaded onto the externally threaded male connection 12 of the first bend housing 10. The first annular spacer 130 has a male connection (first bend housing) end 130 a that abuts the annular shoulder (first male connection surface) 13 on the first bend housing 10 and a female connection (second bend housing) end 130 b that abuts a blunt end (first female connection surface) 123, 323 of the female connection 121, 321. The second annular spacer 131 has a male connection (first bend housing) end 131 a that abuts a blunt end (second male connection surface) 15 of the male connection 12 and an opposed female connection (second bend housing) end 131 b that abuts an annular shoulder (second female connection surface) 125, 325 on an internal surface of the female connection 121, 321. The threaded connection between the male connection 12 and the female connection 121, 321 is then torqued to provide a strong fixed connection between the first bend housing 10 and the second bend housing 120, 320. The width of the first spacer 130 between the male connection end 130 a and the female connection end 130 b and the width of the second spacer 131 between the male connection end 131 a and the female connection end 131 b may be the same or different. The widths of the spacers 130, 131 are such that when the threaded connection between the male connection 12 and the female connection 121, 321 is torqued, the second bend housing high side 124, 324 is aligned with the first bend housing high side 14. The total bend angle (TBA) is the angle between the longitudinal axis 40 of female connection 11 of the first bend housing 10 and the longitudinal axis 142, 342 of the male connection 122, 322 of the second bend housing 120, 320. In other words the total bend angle (TBA) is the angle between the longitudinal axis of one end of the fixed bend assembly and the longitudinal axis of the other end of the fixed bend assembly when the first bend housing and the second bend housing are connected together and torqued. In the first connection position shown in FIGS. 5 and 11, the TBA is 2.5°.

The first connection position of the second and fourth embodiments of the fixed bend assembly 100, 300 shown in FIGS. 5 and 11 has the maximum TBA of 2.5° for the assembly 100, 300. The minimum TBA of 1.5° for the assembly 100, 300 can be achieved by replacing the pair of spacers 130, 131 with a pair of spacers of a different width configured such that the second bend housing high side 124, 324 is positioned 180° relative to the first bend housing high side 14 when the threaded connection between the male connection 12 and the female connection 121, 321 is torqued. It is possible to obtain multiple different TBA between this minimum and maximum TBA using different pairs of spacers of varying widths to yield the desired TBA for a predetermined torque. The predetermined torque can be set through experimentation to determine the optimal torque for a strong fixed connection between the first bend housing and the second bend housing taking into account deformation of the spacers and compression/stretch of the male connection and female connection. The amount of torque can also be varied by small amounts for fine adjustments to yield a desired total bend angle (TBA). It will be appreciated by somebody skilled in the art, that provision of a first bend housing with a different base bend angle (BBA) to the 2° BBA of the first bend housing 10 in the second and fourth embodiments of the assembly 100, 300 and/or provision of a second bend housing with a different offset bend angle (OBA) to the 0.5° OBA of the second bend housing 120, 320 in the second and fourth embodiments of the assembly 100, 300 will result in a different maximum and minimum TBA for the fixed bend assembly.

Provision of a pair of spacers 130, 131 in the releasable connection between the first bend housing 10 and the second bend housing 120, 320 in the second and fourth embodiments of the fixed bend assembly 100, 300 shown in FIGS. 5 and 11 may provide a stronger connection as the second spacer 131 provides additional surface area (male connection end 321 a and female connection end 131 b) against which the connection surfaces of the male connection 12 and female connection 121, 321 (namely blunt end 15 and annular shoulder 125, 325) can be compressed when the threaded connection between the male connection 12 and the female connection 121, 321 is torqued.

In the first to fourth embodiments of the fixed bend assembly 1, 100, 200, 300 disclosed herein, the width of the annular spacers 30, 31, 130, 131 is consistent around the annular spacer such that the annular spacers can be received in any orientation on the male connection or within the female connection to bring about the desired TBA once the male and female connection have been torqued. The width of each annular spacer therefore determines the circumferential orientation of the second bend housing high side 24, 124, 224, 324 relative to the first bend housing high side 14 and thus the TBA of the fixed bend assembly, rather than the rotational orientation of the annular spacer. This may beneficially simplify assembly of the fixed bend assembly as the annular spacer can be received on the male connection or within the female connection in any orientation and the female connection threaded onto the male connection and torqued to provide a fixed bend assembly with a desired TBA.

In alternative embodiments the width of the annular spacer need not be consistent around the annular spacer and the spacer may be positioned in alignment with the first bend housing or the second bend housing through use of design features, marks or the like as would be understood by a person of skill in the art.

The BBA of the first bend housing may be greater than the OBA of the second bend housing, such that the TBA of the fixed bend assembly is greater than zero. For example, the BBA may be from 2 to 50 times greater than the OBA. In these embodiments, the first bend housing provides the main or base bend angle (BBA) and the second bend housing is used to fine tune the TBA depending on the width of the annular spacer (or pair of spacers). For example, the BBA of the first bend housing may be any angle in the range 1° to 5° and the OBA of the second bend housing may be any angle in the range 0.1° to 1°.

In alterative embodiments (not shown), the releasable connection may comprise a female connection on the first bend housing and a male connection on the second bend housing. In these alternative embodiments, the male connection on the second bend housing is provided with a male connection surface against which the one end of the spacer abuts and the female connection on the first bend housing is provided with a female connection surface against which the other end of the spacer abuts when there is threaded connection of the male and female connection.

In alternative embodiments (not shown) an annular spacer may be received in the female connection such that one end of the spacer abuts an annular shoulder (female connection surface) of an internal surface of the female connection and the other end of the spacer abuts a blunt end (male connection surface) of the male connection when there is threaded connection of the male and female connection similar to the second spacer 131 of the second and fourth embodiments of the fixed bend assembly 100, 300 shown in FIGS. 5 and 11. However in these alternative embodiments, there may be no annular spacer received on the male connection and the blunt end of the female connection may abut the annular shoulder of male connection when there is threaded connection of the male and female connection.

Provision of a spacer or a pair of spacers between the connection surfaces of the male and female connections may also increase the life of the fixed bend assembly as the spacer is an easily removable, low cost item that can be replaced if the connection ends of the spacer become worn as a result of torqueing of the threaded connection between the male and female connection.

A kit may be provided with a set of different width annular spacers together with the first bend housing and the second bend housing of the disclosed embodiments. Provision of multiple different width spacers allows the operator to choose the spacer or pair of spacers that provides the desired total bend angle (TBA) for the fixed bend assembly.

The total bend angle (TBA) is dependent on the relative angular position (RAP) between the first bend housing high side and the second bend housing high side. The axial distance between these two locations does not need to be factored in, unless this distance is substantial such that it may affect tool operation. For each fixed bend assembly, the offset bend angle (OBA) of the second bend housing and the base bend angle (BBA) of the first bend housing is fixed. For example, in the first, second, third and fourth embodiments of the fixed bend assembly 1, 100, 200, 300 disclosed herein, the OBA is 0.5° and the BBA is 2°. Once the RAP is known, the total bend angle (TBA) can be calculated using the law of cosines shown in FIG. 15 where:

-   -   a=Offset Bend Angle (OBA)     -   b=Base Bend Angle (BBA)     -   c=Total Bend Angle (TBA)     -   RAP=Relative Angular Position     -   C=180°−Relative Angular Position (RAP)

Referring to FIGS. 6 and 13, which show a perspective view of the first or second embodiment of the fixed bend assembly 1, 100, the relative angular position can be determined by putting a notch or other type of mark 14 a at the first bend housing high side 14 close to the annular shoulder 13 and putting a notch or other type of mark 24 a at the second bend housing high side 24, 124 close to the blunt end 23, 123 of the female connection 21, 121. Spacer 33 is positioned between the annular shoulder 13 and the blunt end 23, 123. Once the threaded connection of the male connection 12 of the first bend housing 10 and the female connection 21, 121 of the second bend housing 20, 120 has been torqued a precision tape can be used to measure around the circumference to measure the length of the arc between mark 14 a and mark 24 a. Knowing the outside diameter (OD) of the first bend housing 10 and the second bend housing 20, 120, the angle (RAP) between mark 14 a and mark 24 a can be calculated based on the measured arc length using the following equation:

${RAP} = {\frac{{arc}\mspace{14mu} {length}}{\pi \mspace{14mu} ({OD})} \times 360}$

The RAP can be achieved by rotation of mark 24 a either clockwise or counter clockwise relative to mark 14 a. Other alternative methods can be used to calculate the RAP as would be understood by a person skilled in the art.

FIGS. 12 and 14 show a perspective view of the third or fourth embodiment of the fixed bend assembly 200, 300. There is a notch or other type of mark 224 a at the second bend housing high side 224, 324 close to the blunt end 223, 323 of the female connection 221, 321 and mark 14 a is at the first bend housing high side 14 close to the annular shoulder 13. Spacer 33 is positioned between the annular shoulder 13 and the blunt end 223, 323. Once the threaded connection of the male connection 12 of the first bend housing 10 and the female connection 221, 321 of the second bend housing 220, 320 has been torqued a precision tape can be used to measure around the circumference to measure the length of the arc between mark 14 a and mark 224 a. Knowing the outside diameter (OD) of the first bend housing 10 and the second bend housing 220, 320, the angle (RAP) between mark 14 a and mark 224 a can be calculated based on the measured arc length using the equation given above with reference to FIGS. 6 and 13. The RAP can be achieved by rotation of mark 224 a either clockwise or counter clockwise relative to mark 14 a. Other alternative methods can be used to calculate the RAP as would be understood by a person skilled in the art.

In some embodiments, the spacer may be provided with a visual guide to help achieve the correct RAP. As shown in FIGS. 6, 12, 13 and 14 spacer 33 has a notch or other type of mark 33 a on its outer diameter. The mark 33 a is an optional feature and need not be present. If present, mark 33 a can be used as a visual guide to achieve the correct RAP when the first bend housing 10 and second bend housing 20, 120, 220, 320 are connected together and torqued.

In the embodiments shown in FIGS. 6 and 12, the spacer 33 is fixed relative to the first bend housing 10. The spacer 33 comprises a male connection end and a female connection end and the surface of the male connection end may have ridges, grooves, castellation's, v-notches or some other design feature (not shown) which engage or mesh with a corresponding profile of ridges, grooves, castellation's, v-notches or some other design feature (not shown) on the surface of the annular shoulder (male connection surface) 13 of the first bend housing 10. Additionally or alternatively, the internal surface of the spacer 33 may have ridges, grooves, castellation's, v-notches or some other design feature (not shown) which mesh or engage with a corresponding profile of ridges, grooves, castellation's, v-notches or some other design feature (not shown) on the external surface of the male connection 12 of the first bend housing 10 that receives the spacer 33. For example, the external surface of the male connection 12 may include a spline (not shown) that meshes with grooves on the internal surface of the spacer 33. Meshing or engagement of these design features on adjacent surfaces locks the spacer 33 in a fixed position relative to the first bend housing 10. To achieve the correct RAP, the second bend housing 20, 120, 220, 320 can be torqued until the mark 24 a, 224 a aligns with the mark 33 a on the spacer 33 as shown in FIGS. 6 and 12. Mark 33 a thereby provides a visual indicator to allow the operator to torque the connection the correct amount to achieve the desired RAP.

In the embodiments shown in FIGS. 13 and 14, the spacer 33 is fixed relative to the second bend housing 20, 120, 220, 320. The spacer 33 comprises a male connection end and a female connection end the surface of the female connection end may have ridges, grooves, castellation's, v-notches or some other design feature (not shown) which engage or mesh with a corresponding profile of ridges, grooves, castellation's, v-notches or some other design feature (not shown) on the surface of the blunt end (female connection surface) 23, 123, 223, 323 of the second bend housing 20, 120, 220, 320. Meshing or engagement of these design features on adjacent surfaces locks the spacer 33 in a fixed position relative to the second bend housing 20, 120, 220, 320. To achieve the correct RAP, the second bend housing 20, 120, 220, 320 and spacer 'can be torqued until the mark 33 a on the spacer 33 aligns with the mark 14 a on the first bend housing 10 as shown in FIGS. 13 and 14. Mark 33 a thereby provides a visual indicator to allow the operator to torque the connection the correct amount to achieve the desired RAP.

In alternative embodiments (not shown), the second bend housing may include a male connection which releasably connects with a female connection of the first bend housing. In these alternative embodiments, the spacer may have a mark or other visual indicator on its external surface to allow the operator to torque the connection the correct amount to achieve the desired RAP.

In one of these alternative embodiments there may be a mark or other visual indicator on the external surface of the second bend housing close to the annular shoulder (male connection surface) of the second bend housing and the spacer may be fixed relative to the female connection of the first bend housing. The surface of the female connection end of the spacer may be provided with ridges, grooves, castellation's, v-notches or some other design feature which engage or mesh with a corresponding profile of ridges, grooves, castellation's, v-notches or some other design feature on the blunt end (female connection surface) of the female connection. Meshing or engagement of these design features on adjacent surfaces locks the spacer in a fixed position relative to the first bend housing. To achieve the correct RAP, the second bend housing can be torqued until the mark on the second bend housing aligns with the mark on the spacer.

In another of these alternative embodiments, there may be a mark or other visual indicator on the external surface of the first bend housing close to the blunt end (female connection surface) of the first bend housing and the spacer may be fixed relative to the male connection of the second bend housing. The surface of the male connection end of the spacer may have ridges, grooves, castellation's, v-notches or some other design feature which engage or mesh with a corresponding profile of ridges, grooves, castellation's, v-notches or some other design feature on the surface of the annular shoulder (male connection surface) of the second bend housing. Additionally or alternatively, the internal surface of the spacer may have ridges, grooves, castellation's, v-notches or some other design feature which mesh or engage with a corresponding profile of ridges, grooves, castellation's, v-notches or some other design feature on the external surface of the male connection of the second bend housing that receives the spacer. For example, the external surface of the male connection may include a spline that meshes with grooves on the internal surface of the spacer. Meshing or engagement of these design features on adjacent surfaces locks the spacer in a fixed position relative to the second bend housing. To achieve the correct RAP, the second bend housing and spacer can be torqued until the mark on the spacer aligns with the mark on the first bend housing.

Determining the width of the spacer needed to achieve a desired total bend angle (TBA) for the fixed bend assembly can be done by determining the relation between axial movement and angular rotation between the first bend housing and the second bend housing. This can be done in two ways as follows:

The first method is to utilize timing/positioning of the starting point of the threaded connections between the first bend housing and the second bend housing. This provides a known distance between connection seal faces and the angular relative rotation as the housings thread together. Compensating for deflection on contact faces, stretch/compression of connection threads, and spacer deformation when the threads are torqued, a calculated spacer width can be predetermined which gives the relative angular position between the first bend housing high side and the second bend housing high side to provide the desired total bend angle (TBA) of the assembly once torqued.

The second method is to utilize a gauge spacer of predetermined width to find the relative angular position (RAP) between the first bend housing high side and the second bend housing high side when torqued. Once the RAP is known for that gauge spacer, adjustments to increase or decrease the spacer width can be made to achieve the final desired RAP, and thus the desired total bend angle (TBA) of the assembly when torqued.

Once the required width of the spacer is determined to achieve a desired TBA for the fixed bend assembly, the spacer (or pair of spacers) may be precision machined to the required width. The fixed bend assembly comprising the first bend housing, second bend housing and machined spacer (or pair of spacers) can then be used to achieve the desired TBA. For example, the fixed bend assembly can be used in the field to create a desired bend in a drill string being used to drill an oil or gas well. It is generally more cost effective to precision machine a spacer (or pair of spacers) to achieve a desired TBA for the fixed bend assembly of the present embodiments than it is to precision machine a new fixed bend for each desired TBA such as the fixed bend described above with reference to Prior Art FIG. 2. The fixed bend assembly of the present embodiments may therefore be a cost effective alternative to known fixed bends.

The total bend angle (TBA) is dependent on the relative angular position (RAP) between the first bend housing high side and the second bend housing high side. The axial distance between these two locations does not need to be factored in, unless this distance is substantial such that it may affect tool operation. For each fixed bend assembly, the offset bend angle (OBA) of the second bend housing and the base bend angle (BBA) of the first bend housing is fixed. For example, in the first, second, third and fourth embodiments of the fixed bend assembly 1, 100, 200, 300 disclosed herein, the OBA is 0.5° and the BBA is 2°. Once the RAP is known, the total bend angle (TBA) can be calculated using the following law of cosines:

FIG. 7 is a chart showing the total bend angle (TBA) as a function of the relative angular position (RAP) using the above law of cosines to calculate TBA (c). This chart is calculated for the first, second, third and fourth embodiments of the fixed bend assembly 1, 100, 200, 300 disclosed herein, where the OBA (a) is fixed at 0.5° and the BBA (b) is fixed at 2° providing a maximum TBA of 2.5° and a minimum TBA of 1.5°. A similar chart can be produced to show the TBA as a function of RAP for other fixed bend assemblies that have a different fixed OBA (a) and/or different fixed BBA (b).

Referring now to FIG. 8, there is shown vector diagram representations of the first, second, third and fourth embodiments of the fixed bend assembly 1, 100, 200, 300 disclosed herein at different relative angular positions (RAP). The vector diagrams are super-imposed over an axial cross section of the first bend housing 10 taken through the bend section 10 b where the contact pad 50 is positioned. View A is equivalent to View C and shows the following:

-   -   a=offset bend angle (OBA)     -   ah=second bend housing high side     -   b=base bend angle (BBA)     -   bh=first bend housing high side     -   c=total bend angle (TBA)     -   ch=total bend angle high side     -   ci=total bend angle low side     -   RAP=relative angular position between bh and ah     -   A=relative angular position between bh and ch

As discussed above the first, second, third and fourth embodiments of the fixed bend assembly 1, 100, 200, 300 disclosed herein have a fixed OBA (a) of 0.5° and a fixed BBA (b) of 2.0°. In View B the RAP is 126° and the TBA (c) is 1.75°. In View C the RAP is 117° and the TBA (c) is 1.83°. In View D the RAP is 97° and the TBA (c) is 2.0°. In View E the RAP is 66° and the TBA (c) is 2.25°. In View F the RAP is 0° and the TBA (c) is 2.5° (i.e. the maximum TBA) and in view G the RAP is 180° and the TBA (c) is 1.5° (i.e. the minimum TBA). The TBA and RAP for each of Views B-G shown in FIG. 8 tie in with the chart shown in FIG. 7.

The fixed bend assembly of the disclosed embodiments generally has increased downhole reliability and may beneficially maintain a consistent bend angle throughout the duration of the life of the assembly and is less likely to relax over time during operation, which typically occurs with fixed bends currently used. However, should the fixed bend assembly of the disclosed embodiments relax during drilling or hard surface pad repair, adjustments to the spacer width can be made in the shop to bring the total bend angle (TBA) back to the TBA originally required for that drilling motor. Furthermore, instead of requiring an inventory of 3-4 fixed bends with different angles, the fixed bend assembly of the disclosed embodiments can achieve the same angle variation through use of different width spacers which are easier and less costly to produce than multiple fixed bends.

The fixed bend assembly of the disclosed embodiments may also be more robust and less likely to crack or result in connection back offs compared to known adjustable assemblies. The fixed bend assembly of the disclosed embodiments can therefore be used for drilling in aggressive conditions and reaming applications. As the fixed bend assembly of the disclosed embodiments comprises only two major components (the first bend housing and the second bend housing) compared to the four major components generally required for known adjustable assemblies it may also be less costly to manufacture and repair.

The fixed bend assembly of the disclosed embodiments can be used for any type of downhole tool requiring a bend and need not be specific to a drilling motor. Furthermore, the fixed bend assembly of the disclosed embodiments may be used in non-oil and gas related tools which require a similar function.

It is contemplated that any part of any aspect or embodiment discussed in this specification can be implemented or combined with any part of any other aspect or embodiment discussed in this specification.

While particular embodiments have been described in the foregoing, it is to be understood that other embodiments are possible and are intended to be included herein. It will be clear to any person skilled in the art that modifications of and adjustments to the foregoing embodiments, not shown, are possible. 

1. A fixed bend assembly comprising: (a) a first bend housing comprising a tubular housing with a first end, a second end and a bore therethrough, wherein a longitudinal axis of the first end of the first bend housing is offset relative to a longitudinal axis of the second end of the first bend housing; (b) a second bend housing comprising a tubular housing with a first end, a second end and a bore therethrough, wherein a longitudinal axis of the first end of the second bend housing is offset relative to a longitudinal axis of the second end of the second bend housing; and (c) an annular spacer comprising an external surface and an internal surface extending between a first end and an opposed second end, wherein a width of the annular spacer between the first end and the second end is consistent around the annular spacer, wherein the first or second end of the first bend housing comprises a first connection end and the first or second end of the second bend housing comprises a second connection end, and wherein one of the first or second connection ends is a male connection with an externally threaded surface and the other of the first or second connection ends is a female connection with an internally threaded surface, wherein the first bend housing and second bend housing are connectable by threaded connection of the male and female connection with the annular spacer positioned between the first bend housing and the second bend housing, and wherein the width of the annular spacer determines a circumferential orientation of a high side of the first bend housing relative to a high side of the second bend housing when the first bend housing and second bend housing are connected by the threaded connection to provide a total bend angle of the fixed bend assembly, whereby the total bend angle is an angle between a longitudinal axis of one end of the fixed bend assembly and a longitudinal axis of the opposite end of the fixed bend assembly when the first bend housing and the second bend housing are connected.
 2. The fixed bend assembly of claim 1, wherein the longitudinal axis of the first end of the first bend housing is offset relative to the longitudinal axis of the second end of the first bend housing by a first angle and the longitudinal axis of the first end of the second bend housing is offset relative to the longitudinal axis of the second end of the second bend housing by a second angle, and wherein the first angle is greater than the second angle.
 3. The fixed bend assembly of claim 1, wherein the annular spacer is received on the male connection, and wherein one of the first or second ends of the annular spacer is a male connection end which abuts an annular shoulder of an external surface of the male connection and the other of the first or second ends of the annular spacer is a female connection end which abuts a blunt end of the female connection when there is threaded connection of the male and female connection.
 4. The fixed bend assembly of claim 3, wherein the internal surface, the male connection end, or both the internal surface and the male connection end of the annular spacer has a design feature which engages with a corresponding design feature on the external surface, the annular shoulder, or both the external surface and the annular shoulder of the male connection respectively to fix the annular spacer in position relative to the male connection, and wherein the external surface of the annular spacer has a first mark thereon and the external surface of the female connection has a second mark thereon and positioning of the first and second marks is such that a desired total bend angle of the fixed bend assembly is achieved by alignment of the first mark and the second mark when there is threaded connection of the male and female connection.
 5. The fixed bend assembly of claim 3, wherein the female connection end of the annular spacer has a design feature which engages with a corresponding design feature on the blunt end of the female connection to fix the annular spacer in position relative to the female connection, and wherein the external surface of the annular spacer has a first mark thereon and an external surface of the first or second bend housing that includes the male connection has a second mark thereon and positioning of the first and second marks is such that a desired total bend angle of the fixed bend assembly is achieved by alignment of the first mark and the second mark when there is threaded connection of the male and female connection.
 6. The fixed bend assembly of claim 1, wherein the annular spacer is received within the female connection, and wherein one of the first or second ends of the annular spacer abuts a blunt end of the male connection and the other of the first or second ends of the annular spacer abuts an annular shoulder of an internal surface of the female connection when there is threaded connection of the male and female connection.
 7. The fixed bend assembly of claim 1 comprising a pair of spacers with a first annular spacer comprising an external surface and an internal surface extending between a first male connection end and a first female connection end and a second annular spacer comprising an external surface and an internal surface extending between a second male connection end and a second female connection end, and wherein: the male connection has a first male connection surface and the female connection has a first female connection surface, wherein the first male connection surface abuts the first male connection end of the first annular spacer and the first female connection surface abuts the first female connection end of the first annular spacer when there is threaded connection of the male and female connection; and the male connection has a second male connection surface and the female connection has a second female connection surface, wherein the second male connection surface abuts the second male connection end of the second annular spacer and the second female connection surface abuts the second female connection end of the second annular spacer when there is threaded connection of the male and female connection.
 8. The fixed bend assembly of claim 7, wherein the first male connection surface is an annular shoulder of an external surface of the male connection and the first female connection surface is a blunt end of the female connection, and the second male connection surface is a blunt end of the male connection and the second female connection surface is an annular shoulder of an internal surface of the female connection, and wherein the first annular spacer is received on the male connection and the second annular spacer is received within the female connection.
 9. The fixed bend assembly of claim 8, wherein the internal surface, the first male connection end or both the internal surface and the first male connection end of the first annular spacer has a design feature which engages with a corresponding design feature on the external surface of the male connection, the annular shoulder of the male connection, or both the external surface and the annular shoulder of the male connection respectively to fix the first annular spacer in position relative to the male connection, and wherein the external surface of the first annular spacer has a first mark thereon and an external surface of the female connection has a second mark thereon and positioning of the first and second marks is such that a desired total bend angle of the fixed bend assembly is achieved by alignment of the first mark and the second mark when there is threaded connection of the male and female connection.
 10. The fixed bend assembly of claim 8, wherein the first female connection end of the first annular spacer has a design feature which engages with a design feature on the blunt end of the female connection to fix the first annular spacer in position relative to the female connection, and wherein the external surface of the first annular spacer has a first mark thereon and an external surface of the first or second bend housing that includes the male connection has a second mark thereon and positioning of the first and second marks is such that a desired total bend angle of the fixed bend assembly is achieved by alignment of the first mark and the second mark when there is threaded connection of the male and female connection.
 11. A kit comprising: (i) a first bend housing comprising a tubular housing with a first end, a second end and a bore therethrough, wherein a longitudinal axis of the first end of the first bend housing is offset relative to a longitudinal axis of the second end of the first bend housing; (ii) a second bend housing comprising a tubular housing with a first end, a second end and a bore therethrough, wherein a longitudinal axis of the first end of the second bend housing is offset relative to a longitudinal axis of the second end of the second bend housing; and (iii) a plurality of annular spacers, each of the plurality of annular spacers comprising an external surface and an internal surface extending between a first end and a second end, wherein a width of the annular spacer between the first end and the second end is different for different annular spacers of the plurality of annular spacers, wherein the first or second end of the first bend housing is configured to connect with the first or second end of the second bend housing through a releasable connection to form a fixed bend assembly with one of the plurality of annular spacers positioned between the first bend housing and the second bend housing when the first bend housing and the second bend housing are connected by the releasable connection, and wherein a total bend angle of the fixed bend assembly is variable by positioning different annular spacers of the plurality of annular spacers between the first bend housing and the second bend housing, whereby the total bend angle of the fixed bend assembly is an angle between a longitudinal axis of one end of the fixed bend assembly and a longitudinal axis of the opposite end of the fixed bend assembly when the first bend housing and the second bend housing are connected by the releasable connection.
 12. The kit of claim 11, wherein the longitudinal axis of the first end of the first bend housing is offset relative to the longitudinal axis of the second end of the first bend housing by a first angle and the longitudinal axis of the first end of the second bend housing is offset relative to the longitudinal axis of the second end of the second bend housing by a second angle, and wherein the first angle is greater than the second angle.
 13. The kit of claim 11, wherein the first or second end of the first bend housing configured to connect with the first or second end of the second bend housing comprises a first connection end, and the first or second end of the second bend housing configured to connect with the first or second end of the first bend housing comprises a second connection end, and wherein one of the first or second connection ends is a male connection and the other of the first or second connection ends is a female connection, and the releasable connection comprises a male and female connection.
 14. The kit of claim 13, wherein the male connection has an externally threaded surface and the female connection has an internally threaded surface, and the releasable connection is a threaded connection of the male and female connection.
 15. The kit of claim 13, wherein the annular spacer is received on the male connection, and wherein one of the first or second ends of the annular spacer is a male connection end which abuts an annular shoulder of an external surface of the male connection and the other of the first or second ends of the annular spacer is a female connection end which abuts a blunt end of the female connection when there is connection of the male and female connection.
 16. The kit of claim 15, wherein the internal surface, the male connection end, or both the internal surface and the male connection end of at least one annular spacer of the plurality of annular spacers has a design feature which engages with a corresponding design feature on the external surface of the male connection, the annular shoulder, or both the external surface and the annular shoulder of the male connection respectively to fix the at least one annular spacer in position relative to the male connection, and wherein the external surface of the at least one annular spacer has a first mark thereon and the external surface of the female connection has a second mark thereon and positioning of the first and second marks is such that a desired total bend angle of the fixed bend assembly is achieved by alignment of the first mark and the second mark when there is connection of the male and female connection.
 17. The kit of claim 15, wherein the female connection end of at least one annular spacer of the plurality of annular spacers has a design feature which engages with a corresponding design feature on the blunt end of the female connection to fix the at least one annular spacer in position relative to the female connection, and wherein the external surface of the at least one annular spacer has a first mark thereon and an external surface of the first or second bend housing that includes the male connection has a second mark thereon and positioning of the first and second marks is such that a desired total bend angle of the fixed bend assembly is achieved by alignment of the first mark and the second mark when there is connection of the male and female connection.
 18. The kit of claim 13, wherein the annular spacer is received within the female connection, and wherein one of the first or second ends of the annular spacer abuts a blunt end of the male connection and the other of the first or second ends of the annular spacer abuts an annular shoulder of an internal surface of the female connection when there is connection of the male and female connection.
 19. A kit comprising: (i) a first bend housing comprising a tubular housing with a first end, a second end and a bore therethrough, wherein a longitudinal axis of the first end of the first bend housing is offset relative to a longitudinal axis of the second end of the first bend housing; (ii) a second bend housing comprising a tubular housing with a first end, a second end and a bore therethrough, wherein a longitudinal axis of the first end of the second bend housing is offset relative to a longitudinal axis of the second end of the second bend housing; and (iii) a plurality of pairs of annular spacers, each pair of annular spacers comprising a first annular spacer and a second annular spacer, the first annular spacer comprising an external surface and an internal surface extending between a first male connection end and a first female connection end, the second annular spacer comprising an external surface and an internal surface extending between a second male connection end and a second female connection end, wherein a width of the first annular spacer between the first male connection end and the first female connection end and/or a width of the second annular spacer between the second male connection end and the second female connection end is different for different pairs of annular spacers of the plurality of pairs of annular spacers, wherein the first or second end of the first bend housing comprises a first connection end and the first or second end of the second bend housing comprises a second connection end, and wherein one of the first or second connection ends is a male connection with a first male connection surface and a second male connection surface and the other of the first or second connection ends is a female connection with a first female connection surface and a second female connection surface, wherein the male connection and the female connection are configured to releasable connect to form a fixed bend assembly with the first annular spacer positioned between the first male connection surface and the first female connection surface and the second annular spacer positioned between the second male connection surface and the second female connection surface when there is connection of the male and female connection, and wherein a total bend angle of the fixed bend assembly is variable by positioning different pairs of the different pairs of annular spacers between the male and female connection surfaces and connecting the male and female connection, whereby the total bend angle of the fixed bend assembly is an angle between a longitudinal axis of one end of the fixed bend assembly and a longitudinal axis of the opposite end of the fixed bend assembly when the first bend housing and the second bend housing are connected.
 20. The kit of claim 19, wherein the longitudinal axis of the first end of the first bend housing is offset relative to the longitudinal axis of the second end of the first bend housing by a first angle and the longitudinal axis of the first end of the second bend housing is offset relative to the longitudinal axis of the second end of the second bend housing by a second angle, and wherein the first angle is greater than the second angle.
 21. The kit of claim 19, wherein the male connection has an externally threaded surface and the female connection has an internally threaded surface, and the releasable connection is a threaded connection of the male and female connection.
 22. The kit of claim 20, wherein the first male connection surface is an annular shoulder of an external surface of the male connection and the first female connection surface is a blunt end of the female connection, the second male connection surface is a blunt end of the male connection and the second female connection surface is an annular shoulder of an internal surface of the female connection, wherein the first annular spacer is received on the male connection with the first male connection end abutting the annular shoulder of the male connection and the first female connection end abutting the blunt end of the female connection when there is connection of the male and female connection, and wherein the second annular spacer is received within the female connection with the second male connection end abutting the blunt end of the male connection surface and the second female connection end abutting the annular shoulder of the female connection when there is connection of the male and female connection.
 23. The kit of claim 22, wherein the internal surface, the first male connection end or both the internal surface and the first male connection end of the first annular spacer has a design feature which engages with a corresponding design feature on the external surface, the annular shoulder, or both the external surface and the annular shoulder of the male connection respectively to fix the first annular spacer in position relative to the male connection, and wherein the external surface of the first annular spacer has a first mark thereon and an external surface of the female connection has a second mark thereon and positioning of the first and second marks is such that a desired total bend angle of the fixed bend assembly is achieved by alignment of the first mark and the second mark when there is connection of the male and female connection.
 24. The kit of claim 22, wherein the first female connection end of the first annular spacer has a design feature which engages with a design feature on the blunt end of the female connection to fix the first annular spacer in position relative to the female connection, and wherein the external surface of the first annular spacer has a first mark thereon and an external surface of the first or second bend housing that includes the male connection has a second mark thereon and positioning of the first and second marks is such that a desired total bend angle of the fixed bend assembly is achieved by alignment of the first mark and the second mark when there is connection of the male and female connection. 